1. Field of the Invention
The present application relates to a substrate for an organic electronic device (OED), a method of manufacturing the same, and a use thereof.
2. Discussion of Related Art
An OED is a device including at least one of layers of, for example, an organic material, which can conduct a current. Types of the OED include an organic light emitting device (OLED), an organic photovoltaic cell, an organic photo conductor (OPC), or an organic transistor.
Conventionally, the OLED, which is a representative of the OED, sequentially includes a substrate, a first electrode layer, an organic layer, and a second electrode layer. The OLED may be classified as a top emission device, a bottom emission device, and a both-side emission device. In a structure, which is called as a bottom emission device, a first electrode layer may be formed as a transparent electrode layer, and a second electrode layer may be formed as a reflective electrode layer, in a structure, which is called as a top emission device, a first electrode layer may be formed as a reflective electrode layer, and a second electrode layer may be formed as a transparent electrode layer, and in a structure which is called as a both-side emission device, both of a first electrode layer and a second electrode layer may be transparent electrode layers. Electrons and holes injected by the electrode layers may be recombined in an emitting layer present in an organic layer, thereby generating light.
Recently, the increasing attention to a flexible OLED causes an increase in demand for technology of substituting a glass substrate with a plastic substrate in a structure of the OLED.
However, the plastic substrate is vulnerable to permeation of water and oxygen. Particularly, when a display device including an OLED using the plastic substrate is manufactured, the water and oxygen are permeated from the substrate, resulting in reducing a lifespan of the OLED.
Conventionally, to prevent the permeation of the water and oxygen to the plastic substrate, a single inorganic barrier layer was formed on a surface of the plastic substrate, or a structure in which an inorganic metal layer and an organic layer are stacked or a structure in which a plurality of inorganic barrier layers are stacked by means of a pressure-sensitive adhesive layer was used. However, despite such a structure, an adhesive strength between the barrier layer and the plastic substrate was decreased due to partial crystallization of the barrier layer, or a water vapor transmission rate (WVTR) required by an OLED display was not satisfied due to permeation of water.
In addition, because of such a structure of the inorganic barrier layer, for example, in the structure called as a bottom emission device, the first electrode layer, which is used as a transparent electrode layer, was affected by a stress generated by the underlying inorganic barrier layer, resulting in film separation or generation of a crack.